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/*******************************************************************************
* Copyright (c) 2000, 2007 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.swt.snippets;
/*
* Canvas snippet: update a portion of a Canvas frequently
*
* For a list of all SWT example snippets see
* http://www.eclipse.org/swt/snippets/
*/
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
public class Snippet275 {
static String value;
public static void main (String[] args) {
final int INTERVAL = 888;
final Display display = new Display ();
final Image image = new Image (display, 750, 750);
GC gc = new GC (image);
gc.setBackground (display.getSystemColor (SWT.COLOR_RED));
gc.fillRectangle (image.getBounds ());
gc.dispose ();
Shell shell = new Shell (display);
shell.setBounds (10, 10, 790, 790);
final Canvas canvas = new Canvas (shell, SWT.NONE);
canvas.setBounds (10, 10, 750, 750);
canvas.addListener (SWT.Paint, new Listener () {
public void handleEvent (Event event) {
value = String.valueOf (System.currentTimeMillis ());
event.gc.drawImage (image, 0, 0);
event.gc.drawString (value, 10, 10, true);
}
});
display.timerExec (INTERVAL, new Runnable () {
public void run () {
if (canvas.isDisposed ()) return;
// canvas.redraw (); // <-- bad, damages more than is needed
GC gc = new GC (canvas);
Point extent = gc.stringExtent (value + '0');
gc.dispose ();
canvas.redraw (10, 10, extent.x, extent.y, false);
display.timerExec (INTERVAL, this);
}
});
shell.open ();
while (!shell.isDisposed ()){
if (!display.readAndDispatch ()) display.sleep ();
}
image.dispose ();
display.dispose ();
}
}
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